The present invention generally relates to the field of climate control and more particularly, is directed to a fluid flow filter which traps and prevents contaminants from reaching environmentally sensitive areas of an electronic device.
Many electronic devices require that the climate in which they operate be maintained within a certain range. Typically, environmental factors such as temperature, temperature stability, humidity and air quality are of paramount concern with respect to the operating life of the equipment and its mean time between failures (MTBF).
Continued exposure to elevated temperatures is one of the primary causes of premature failure in well-designed electronic equipment. Most equipment produces heat as an unwanted by-product. Thus, means must be provided to dissipate a certain amount of the heat so that the device can safely operate within its designed environmental specification.
A common and well accepted method of dissipating heat is to use some form of heat exchange device. Such a device can be as simple as a metal heat fin attached to the heat generating device and is often referred to as a heat sink. Other methods of dissipating heat rely on forced air cooling where air is blown or pulled over the heat generating device in order to absorb and carry away as much heat as possible.
Forced air cooling subjects the device to contaminants brought in by the air from the environment outside of the device. These contaminants can include foreign objects such as dust particles and water vapor. Absent some form of filtering or trapping of these contaminants to prevent their introduction into the device, the operating life of the device may well be adversely effected.
Accordingly, there is known in the art a number of techniques for filtering air before its introduction into a device for the purpose of controlling environmental factors such as temperature and humidity. (For purpose of this specification, the words “air” and “fluid” are used interchangeably.) Techniques known in the art generally are deficient for a number of reasons. These deficiencies include over restriction of air flow in order to insure adequate filtration, providing sufficient air flow at the expense of efficient filtration, complicated design and high cost.
One example of environment control and air flow filtration that is commonly needed in an electronic device is that of a hard disk drive. A hard drive is used in a computer system to store data. As the need for storage capacity has increased over the years, so to has the complexity of hard drives and their sensitivity to the internal environment in which they operate.
Data in a hard disk drive is stored on a magnetic platter. The drive operates by a read/write head hovering a few micros above the rotating platter. Characteristics which determine the storage capacity of the drive and the speed at which data can be written to and read from the drive include the rotating speed of the media and the proximity of the read/write head to the surface of the platter.
As data packing density increases in order to keep pace with the need for more storage capacity, the sensitivity of the magnetic platter to elevated temperatures, temperature variations and the presence of contaminates increase as well. In addition, the presence of contaminants raises the likelihood that a stray particle will become lodged between the read/write head and the platter, thus causing data read/write errors and possible destruction of the hard drive.
Failure to take adequate safeguards to prevent temperature extremes and the introduction of contaminates takes on added significance in high capacity hard disk drives. In high capacity drives, the magnetic platter rotates at a higher speed and the distance between the data read/write heads and the surface of the platter is smaller. Thus, the platters in modern high capacity drives are more sensitive to warping caused by un-controlled temperature variations and stray contaminates than their lower capacity counterparts.
Thus, there is a need in the art for an air flow filter for preventing the inadvertent introduction of contaminates into the drive. Such filters, however, are deficient for a number or reasons as pointed out above.